Break-even ACoS and PPC Bid Ceiling Calculator

ACoS (Advertising Cost of Sale) is ad spend divided by ad-attributed sales, expressed as a percentage - lower is better. ROAS (Return on Ad Spend) is the inverse ratio, sales divided by spend - higher is better. Both describe the same relationship, just as different fractions.

Not necessarily. A very low ACoS on a small budget can mean you are under-bidding and missing profitable volume you could otherwise capture. The right target is the ACoS where you hit your desired profit per unit - going lower than that just leaves growth on the table, especially during a launch phase where you may intentionally run above break-even to gain rank.

Yes - it should be your selling price minus product cost, referral fee, and fulfilment fee, before subtracting anything for advertising. If you are not sure of that number, run your numbers through the Marketplace Profitability Calculator on the homepage first.

A higher conversion rate means fewer clicks are needed per sale, so you can afford to pay more per click and still land at the same ACoS. Two listings with identical margins but different conversion rates should bid very differently on the same keyword.

No - break-even and target ACoS are specific to each product's margin, not a single number across your whole catalog. A high-margin product can sustain a much higher ACoS than a thin-margin one before ads stop being profitable.